JP2006147987A - Laser oscillator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a laser oscillator capable of performing easily the optical-axis adjustment of a Q-switch, and especially, perform easily the optical-axis adjustment of a Q-switch in an air-cooled laser oscillator. <P>SOLUTION: The laser oscillator has a rear mirror 4 and an output mirror 7 which form together a resonator optical axis, a laser crystal 5 provided on the resonator optical axis and for performing the stimulated emission of a laser beam, an acoustic element 6 for controlling a laser oscillation by diffracting the laser beam present on the resonator optical axis, a resonator housing for storing the laser crystal and the acoustic element in a hermetic space, an exciting-light feeding portion for making an exciting light incident on the laser crystal, and an exciting-light-path adjusting portion for adjusting the incident path of the exciting light on the laser crystal. Further, the laser oscillator performs the optical-axis adjustment of a Q-switch by changing the incident path of the exciting light. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a laser oscillator, and more particularly to an improvement in a solid-state laser oscillator that generates pulsed laser light using a Q switch.

  In general, a solid-state laser oscillator includes a laser crystal that stimulates and emits laser light, an optical lens that collects excitation light on the laser crystal, a rear mirror and an output mirror that form a resonator optical axis, and a Q that causes pulsed laser light. The switch is constituted by a resonator housing that supports these members.

  A sealed space is formed inside the resonator casing, and the above-mentioned member is accommodated in the sealed space, thereby preventing a decrease in laser output due to dust intrusion. The resonator housing is formed of a material having high thermal conductivity such as metal, and the laser crystal and the Q switch are brought into close contact with the inner wall of the sealed space, so that the heat generated by the laser crystal and the Q switch is resonator. It is discharged outside through the housing.

  When optical pumping is performed in which the optical lens irradiates excitation light to excite the laser crystal, laser light is emitted from the laser crystal. When this laser beam is reciprocated on the resonator optical axis and fed back to the laser crystal, the laser beam is amplified and laser oscillation occurs.

  The Q switch periodically diffracts the laser light on the resonator optical axis, thereby periodically blocking the feedback path, and generating high-power laser light called a giant pulse. That is, the period during which the laser beam on the resonator optical axis is transmitted and the period during which the laser beam is diffracted and deflected outside the resonator optical axis are alternately repeated, and the energy stored in the laser crystal during the deflection period is transmitted through the subsequent transmission period. Output as a steep pulsed laser beam.

  In general, an acousto-optic device (AOM) is used for the Q switch. The acoustooptic device includes a vibrator that generates ultrasonic waves based on an input signal, and a crystal in which a diffraction grating is formed by the ultrasonic waves. That is, the crystal is elastically vibrated by ultrasonic waves, a diffraction grating is formed in the crystal, and laser light is diffracted. Such a Q switch generates intense heat because it vibrates the crystal. For this reason, in the laser oscillator using the Q switch, it is necessary to efficiently exhaust the heat of the Q switch, and in the conventional laser oscillator, a circulation path of the cooling medium (liquid) is provided in the resonator housing and forced. A so-called water-cooling method was adopted.

  As described above, most of the conventional laser devices employ a water-cooling method as an exhaust heat method. However, in the case of the water-cooled type, there is a problem that a cooling medium circulation path must be provided, the structure of the laser oscillator becomes complicated, and the laser oscillator is difficult to downsize.

  Therefore, it is conceivable to adopt an air cooling method instead of the water cooling method as a heat exhaust method of the laser oscillator. However, an air-cooled type that performs cooling by heat radiation or the like without using a cooling medium has a lower exhaust heat efficiency than a water-cooled type. For this reason, further improvement is required to achieve a high-power laser oscillator by air cooling. As such an improvement plan, improvement in the exhaust heat efficiency of the Q switch and suppression of the heat generation amount in the Q switch can be considered.

  In order to improve the exhaust heat efficiency of the Q switch, the heat resistance in the exhaust heat path from the Q switch to the resonator housing must be suppressed, and the exhaust surface of the Q switch is in close contact with the inner wall of the resonator housing It is necessary to make it. Moreover, in order to suppress the heat generation amount in the Q switch, it is necessary to reduce the RF signal power input to the Q switch.

  However, when the power supplied to the Q switch is lowered, the active aperture of the Q switch becomes narrower. For this reason, in the optical axis adjustment work of the Q switch for matching the resonator optical axis with the active aperture, higher accuracy is required than in the case of the water-cooled laser oscillator, and there is a problem that the adjustment work becomes difficult. Moreover, this optical axis adjustment must be performed by moving the Q switch. That is, there is a problem that the optical axis adjustment must be performed while maintaining the state where the heat exhaust surface of the Q switch is in close contact with the inner wall of the resonator housing, and the adjustment work becomes more difficult. there were.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a laser oscillator capable of easily adjusting the optical axis of a Q switch. In particular, an object of the present invention is to provide a laser oscillator capable of easily adjusting the optical axis of a Q switch in an air-cooled laser oscillator.

  A laser oscillator according to a first aspect of the present invention includes a rear mirror and an output mirror that are arranged to face each other and form a resonator optical axis, a laser crystal that is provided on the resonator optical axis and that stimulates and emits laser light; An acousto-optic device that controls laser oscillation by diffracting the laser beam on the resonator optical axis, a resonator housing that houses the laser crystal and acousto-optic device in a sealed space, and excitation light to the laser crystal And an excitation light path adjusting unit for adjusting an incident path of the excitation light to the laser crystal. With such a configuration, the resonator axis can be moved by adjusting the incident path of the excitation light, and the optical axis adjustment of the Q switch can be facilitated.

  The laser oscillator according to the second aspect of the present invention is an optical lens in which the pumping light supply unit transmits the pumping light and the output light from the optical fiber is transmitted through the rear mirror and focused on the laser crystal. The excitation optical axis adjustment unit includes an adjustment mechanism for adjusting the relative positions of the optical fiber and the optical lens in a direction perpendicular to the central axis of the optical lens. With such a configuration, one of the optical fiber cable and the optical lens can be moved to adjust the optical axis of the Q switch, and the optical axis adjustment of the Q switch can be facilitated.

  In the laser oscillator according to a third aspect of the present invention, the pumping light supply unit transmits an optical fiber cable that supplies the pumping light and output light from the optical fiber cable through the rear mirror and focuses the laser crystal on the laser crystal. It comprises an optical lens, and the excitation light axis adjustment unit comprises an adjustment mechanism for adjusting the attachment position of the excitation light supply unit to the resonator housing. With such a configuration, the optical axis of the Q switch can be adjusted by moving both the optical fiber cable and the optical lens with respect to the laser crystal, and the optical axis of the Q switch can be easily adjusted.

  A laser oscillator according to a fourth aspect of the present invention is configured so that the mounting position can be adjusted in a direction parallel to the heat dissipation surface in a state where the heat dissipation surface of the acoustooptic device is in close contact with the inner wall of the sealed space. Acousto-optic element attachment means for attaching an optical element to the resonator housing, and the excitation light axis adjustment unit adjusts the position of the excitation light axis output from the excitation light supply unit in a direction perpendicular to the heat radiating surface. Configured to be adjustable. With such a configuration, it is possible to easily adjust the direction perpendicular to the heat radiating surface where it is difficult to adjust the optical axis of the Q switch.

  ADVANTAGE OF THE INVENTION According to this invention, the laser oscillator which can perform the optical axis adjustment of Q switch easily can be provided. In particular, in an air-cooled laser oscillator, the optical axis adjustment of the Q switch can be facilitated.

Embodiment 1 FIG.
FIG. 1 is an explanatory diagram of the laser oscillator according to the first embodiment of the present invention, and shows a state when adjusting the optical axis of the Q switch. The laser oscillator includes optical lenses 2 and 3, a rear mirror 4, a laser crystal 5, a Q switch 6 and an output mirror 7. The optical fiber cable 8 supplies excitation light generated by an excitation light source (not shown) to the laser oscillator.

  The excitation light emitted from the optical fiber cable 8 enters the optical lens 2 while spreading, and is collimated (collimated) by the optical lens 2. This collimated light is condensed on the laser crystal 5 by the optical lens 3. The two optical lenses 2 and 3 can be replaced with a single optical lens.

  The laser crystal 5 is made of a solid laser medium that stimulates and emits laser light by optical pumping. In other words, if light corresponding to the energy level difference is incident under a state in which an inversion distribution is formed in which the excited state is dominant over the ground state when excited by the excitation light, the same wavelength and the same wavelength as the incident light are incident. Emits phase light.

  The rear mirror 4 and the output mirror 7 constitute a laser resonator together with the laser crystal 5. The rear mirror 4 is a total reflection type mirror that transmits the excitation light from the optical lens 3 to the laser crystal 5 and totally reflects the laser light from the laser crystal 5. The output mirror 7 is a transflective mirror that reflects most of the laser light from the laser crystal 5 and transmits part of the laser light to the outside of the laser resonator. That is, the rear mirror 4 and the output mirror 7 are disposed to face each other with the laser crystal 5 interposed therebetween, and form a resonator optical axis including the laser crystal 5. The resonator optical axis is a path for reciprocating the emitted light of the laser crystal 5 and amplifies the emitted light by re-entering the laser crystal 5 to generate laser light having a uniform wavelength and phase.

  In this laser oscillator, the end face of the laser crystal 5 is irradiated with excitation light via the rear mirror 4. Such an optical pumping method is called an end pumping method as opposed to a side pumping method in which the side surface of the laser crystal 5 is irradiated with excitation light.

  FIG. 2 is an explanatory diagram of the resonator optical axis. The resonator optical axis is defined by the rear mirror 4 and the output mirror 7 and a thermal lens formed in the laser crystal 5 due to the temperature gradient. The laser crystal 5 generates heat when the wavelength of the excitation light is converted into laser light, and a temperature gradient is generated inside the laser crystal 5. In general, since the refractive index of a substance changes according to temperature, a kind of optical lens 5R is formed in the laser crystal 5 by this temperature gradient. This optical lens is called a thermal lens.

  The Q switch 6 is an acousto-optic element disposed on the resonance optical axis, and can diffract the laser light on the resonator optical axis based on the control signal to temporarily stop optical amplification. Such a Q switch 6 has a region in the crystal 61 where the diffraction angle sufficient to stop the optical amplification is obtained, that is, a so-called active aperture. Therefore, it is necessary to adjust the position of the Q switch 6 so that the resonator optical axis coincides with the active aperture. Such adjustment related to the Q switch is referred to as optical axis adjustment.

  In the laser oscillator of FIG. 1, when the incident path of the excitation light to the optical lens 2 is changed, the path of the excitation light in the laser crystal 5 is also changed. For this reason, the temperature distribution in the laser crystal 5 changes, and the optical axis of the resonator moves as the thermal lens effect changes. That is, if the position of the optical fiber cable 8 is moved, the optical axis can be adjusted while the Q switch 6 is fixed.

  FIG. 3 is an explanatory diagram of changes in the thermal lens 5R. When the position of the light exit end of the optical fiber cable 8 is moved in a direction perpendicular to the central axis of the optical lenses 2 and 3, the incident position of the excitation light on the incident surface of the laser crystal 5 changes. For this reason, even if it is a case where a condensing point does not fluctuate, the path | route from an entrance plane to a condensing point changes. Moreover, since most of the excitation light is absorbed in the vicinity of the incident surface, the optical axis of the resonator can be moved by moving the optical fiber cable 8.

  Next, a specific configuration of the laser oscillator according to the first embodiment of the present invention will be described with reference to FIGS.

  4 and 5 are external views showing a configuration example of the laser oscillator according to the first embodiment of the present invention. This laser oscillator oscillates and outputs laser light when excitation light generated by a laser diode (not shown) is input. The resonator housing 1 includes a housing body 10 having an inner space 12 with one surface open, and a lid portion 11 covering the open surface. A fiber connector 13 and a lens holder 14 are attached to the housing body 10. ing. 4 is a perspective view of the laser oscillator, FIG. 5B is a front view of the laser oscillator of FIG. 1 viewed from the opening side, and FIG. It is a top view.

  If the lid 11 is screwed to the casing body 10 and engaged with each other, a sealed space 12 is formed inside the resonator casing 1. A laser crystal 5 and a Q switch 6 are accommodated in the sealed space 12. The lens holder 14 holds the optical lens 2 inside. The fiber connector 13 connects an optical fiber (not shown) that transmits excitation light generated by the laser diode to the laser oscillator. The laser crystal 5 is mounted in the sealed space 12 by a crystal holder 5H that sandwiches the side surface thereof. The Q switch 6 is mounted in the sealed space 12 by a substantially L-shaped Q switch holder 60.

  Each member constituting the laser oscillator needs to be supported while being positioned with high accuracy. Further, when dust enters the resonator housing 1, dust burned by the laser light contaminates the surfaces of the laser crystal 5 and the Q switch 6 and causes a decrease in laser output. Furthermore, it is necessary to efficiently exhaust the heat of the laser crystal 5 and the Q switch 6 from the resonator housing 1. For this reason, it is necessary to use a material excellent in structural strength, airtightness, and thermal conductivity for the resonator housing 1 and is usually formed of a metal with good workability. Here, the resonator housing 1 is made of aluminum, and the housing body 10 is made of an aluminum block formed by cutting or die casting. The crystal holder 5H and the Q switch holder 6H are also made of aluminum.

  The signal connector 6 </ b> C is a connector to which a control signal is input from the outside, and this control signal is input to the Q switch 6. Here, an RF (Radio Frequency) signal is input from the signal connector 6 </ b> C as a control signal for the Q switch 6.

  FIG. 6 is a cross-sectional view taken along the line AA in FIG. 5A, and the alternate long and short dash line in FIG. 5 substantially coincides with the optical axes of the excitation light and the laser light.

  The excitation light incident from the fiber connector 13 is condensed inside the laser crystal 5 by the two optical lenses 2 and 3. The optical lens 2 that collimates the excitation light (collimated) is held in the lens holder 14. The optical lens 3 that condenses the collimated light on the laser crystal 5 is held in the housing body 10. The excitation light incident on the laser crystal 5 is converted in wavelength to become laser light. For example, a wavelength of 808 nm of excitation light is converted to a wavelength of 1064 nm of laser light.

  The rear mirror 4 and the output mirror 7 are opposed to each other with the sealed space 12 interposed therebetween, and form a resonator optical axis including the laser crystal 5 and the Q switch 6.

  As the laser crystal 5, for example, YAG doped with neodymium (Nd) ions (garnet crystal made of yttrium and aluminum) or YVO4 (yttrium vanadate) is used. Heat generated when the excitation light is converted into laser light in the laser crystal 5 is transmitted to the resonator casing 1 through the crystal holder 5H serving as a heat sink, and is radiated to the outside.

  The Q switch 6 can diffract the laser light on the resonator optical axis based on the control signal input from the signal connector 6C. When the Q switch 6 is on, the laser beam on the resonator optical axis is diffracted and deflected outside the resonator optical axis. When the Q switch 6 is off, the laser beam is transmitted as it is. That is, if the Q switch 6 is turned on, the laser light on the resonator optical axis is blocked, and the optical amplification can be temporarily stopped. At this time, since a large excitation energy is accumulated in the laser crystal 5, if the Q switch is turned off after that, a steep and extremely high peak energy laser beam called a giant pulse can be generated. Therefore, high-power pulsed laser light can be generated by periodically turning on / off the Q switch 6.

  FIG. 7 is a diagram showing a detailed configuration example of the Q switch 6. The Q switch 6 is configured by attaching a vibrator 60 called a transducer to a crystal 61. The transducer 60 generates an ultrasonic wave based on an RF signal input from the input terminal 62, and when this ultrasonic wave is propagated to the crystal 61 made of crystal, a diffraction grating is formed in the crystal 61. The

  When the crystal 61 having photoelasticity is vibrated with ultrasonic waves, a periodic stress distribution corresponding to the wavelength of the ultrasonic waves is generated therein. Due to this stress distribution, a periodic distribution of the refractive index is generated inside the crystal 61, and a diffraction grating is formed. Such a diffraction grating is not uniformly generated in the crystal 61, and the diffraction angle of the laser light varies depending on the region in the crystal 61. An active aperture 63 in the figure is a region where laser light can be sufficiently diffracted, and is formed on the vibrator 60 side in the crystal 61 and at a position slightly away from the vibrator 60. For this reason, the Q switch 6 must be arranged so that the optical axis of the resonator coincides with the active aperture 63.

  Further, the on-state Q switch 6 vigorously generates heat because the crystal 61 is vibrated. For this reason, the Q switch holder 6 </ b> H as a heat sink conducts this heat to the housing body 10 and discharges it to the outside of the resonator housing 1. This exhaust heat is performed by an air cooling method that does not involve circulation of the cooling medium, and the exhaust heat efficiency is worse than that of the conventional water cooling method.

  For this reason, it is necessary to further improve the exhaust heat efficiency and to suppress the heat generation of the Q switch 6 itself. That is, one surface (preferably the widest surface) of the crystal 61 is used as a heat removal surface, and is in close contact with the Q switch holder 6H, and the Q switch holder 6H is in close contact with the resonator housing 1. In addition, compared with the conventional water-cooled type, the signal power of the RF signal is reduced to suppress the amount of heat generated in the Q switch 6.

  However, if the RF signal power is lowered, not only the heat generation is reduced, but the active aperture 63 is also narrowed. That is, if heat generation in the Q switch 6 is suppressed, high accuracy is required for positioning of the Q switch 6. Moreover, in order to ensure high heat exhaust efficiency, the heat exhaust surface of the Q switch 6 must be in close contact with the resonator housing 1 via the Q switch holder 6H. For this reason, if it is attempted to adjust the optical axis by positioning the Q switch 6 in the same manner as in the prior art, the work becomes more difficult than in the prior art.

  FIG. 8 and FIG. 9 are diagrams showing an example of how the Q switch 6 is positioned and adjusted. FIG. 8 is a view as seen from the opening side of the housing body 10, and FIG. 9 is a view showing a cross section taken along the line BB of FIG.

  The Q switch 6 is fixed to the Q switch holder 6H, and the Q switch holder 6H is attached to the internal space 12 of the housing body 10 while being positioned. The Q switch holder 6H is positioned using, for example, a spring 65 and a micrometer 66. Specifically, in a state where one side surface of the Q switch holder 6H placed in the housing body 10 is urged by a spring, the micrometer 66 is applied to the side surface facing this. Here, two sets of springs 65 and a micrometer 66 are arranged in a direction parallel to the heat removal surface of the Q switch 6 and perpendicular to the optical axis of the resonator.

  In this state, if the micrometer 66 is operated and the measurement axis is moved in the insertion / removal direction, the position of the Q switch holder 6H can be finely adjusted. In this manner, the Q switch 6 is positioned so that the resonator optical axis passes through the active aperture 63. When the positioning is finished, the four switch screws 64 are used to fix the Q switch holder 6H to the inner wall of the housing body 10, and the spring 65 and the micrometer 66 are removed. By performing such adjustment work, it is possible to adjust the Q switch holder 6H to move or rotate in an arbitrary direction within a plane parallel to the heat removal surface of the Q switch 6.

  On the other hand, the heat release surface of the Q switch 6 is not brought into close contact with the inner wall of the housing body 10 via the Q switch holder 6H. For this reason, in the laser oscillator according to the present embodiment, the position of the Q switch cannot be adjusted in the direction perpendicular to the heat removal surface of the Q switch 6. For this reason, in the laser oscillator according to the present embodiment, the position of the fiber connector 13 is adjusted and the incident position of the excitation light on the optical lens 2 is moved, so that the resonator optical axis is moved to the active aperture 63 of the Q switch 6. Fine adjustments are made to match.

  FIG. 10 is a cross-sectional view showing the main part of FIG. 6 in more detail, and shows a configuration example from the fiber connector 13 to the rear mirror 4.

  The optical lens 3 and the rear mirror 4 are held in the housing body 10. A cylindrical hollow portion is formed in the excitation light incident portion of the housing body 10, and the vicinity of the central axis serves as the excitation light path. This hollow portion is provided with a small through-hole on the excitation light emission side (that is, on the laser crystal 5 side), and the excitation light incident side is largely opened. The optical lens 3 and the rear mirror 4 are inserted from the opening and are held in the hollow portion. The inner wall of the hollow portion is threaded, and the optical lens 3 and the rear mirror 4 are respectively fixed in the housing body 10 by ring screws 3R and 4R engaged with the inner wall.

  The lens holder 14 has a disk shape having a cylindrical hollow portion on the central axis thereof, and the vicinity of the central axis is a path for excitation light. The hollow portion is provided with a small through-hole on the excitation light incident side, and is largely opened on the excitation light emission side. The optical lens 2 is inserted from the opening and is held in the hollow portion. The inner wall of the hollow portion is threaded, and the optical lens 2 is fixed in the lens holder 14 by a ring screw 2R engaged with the inner wall. Further, the lens holder 14 has a cylindrical protruding portion in which the inner wall of the hollow portion is extended to the excitation light emitting side. The protrusion has an outer wall threaded, and the lens holder 14 is engaged with the housing body 10 by engaging the outer wall with the inner wall of the hollow portion of the housing body 10.

  The fiber connector 13 has a hollow cylindrical shape having a flange portion 13F at one end, and the vicinity of the central axis serves as a path for excitation light. The other end of the fiber connector 13 is provided with a fiber attachment portion 13C to which the output end of the optical fiber cable 8 is connected.

  Screw holes are formed at positions corresponding to each other in the flange portion 13 </ b> F of the fiber connector 13 and the outer peripheral portion of the lens holder 14, and the fiber connector 13 is fixed to the lens holder 14 using an attachment screw 16.

  Here, the screw hole formed in the fiber connector 13 has an inner diameter larger than the outer shape of the shaft portion of the mounting screw 16, and the position of the fiber connector 13 with respect to the optical lens 2 when fastened by the mounting screw 16. Can be fine-tuned. That is, the fiber connector 13 can be positioned by moving in an arbitrary direction within a plane perpendicular to the central axis of the optical lens 2. For this reason, the incident position of the excitation light with respect to the optical lens 2 can be adjusted.

  The output mirror 7 is held in the housing body 10 and can be adjusted in angle. In this laser oscillator, since the rear mirror 4 is fixed, the angle adjustment mechanism of the output mirror 7 is for causing the incident laser light to the output mirror 7 to enter the reflecting surface perpendicularly, and the angle adjustment is performed. The optical axis of the resonator is not arbitrarily moved using a mechanism.

  The optical axis of the Q switch 6 is adjusted after the output mirror 7 is adjusted. That is, after the output mirror 7 is adjusted, the Q switch is adjusted by a method similar to the conventional method, and then the fine adjustment is performed by positioning the fiber connector 13. During this fine adjustment, the thermal lens changes, so that the output mirror 7 is readjusted after the fiber connector 13 is positioned. Further, if necessary, the positioning of the fiber connector 13 and the readjustment of the output mirror 7 are repeated.

  According to the present embodiment, the fiber connector 13 that holds the light exit end of the optical fiber cable 8 can be adjusted, and the incident position of the excitation light with respect to the optical lenses 2 and 3 can be adjusted. For this reason, by finely adjusting the attachment position of the fiber connector 13, the resonator optical axis can be matched with the active aperture 63 while the Q switch 6 is fixed. Therefore, the optical axis adjustment of the Q switch 6 can be facilitated. In particular, it is suitable for an air-cooled laser oscillator in which the operation of adjusting the optical axis is difficult and high-precision adjustment is required.

  In this embodiment, an example of a laser oscillator that employs an end pumping method has been described. However, the present invention is not limited to such a case. That is, even in the case of the side pumping method, the optical axis of the Q switch 6 can be adjusted by changing the thermal lens 5R in the laser crystal 5.

  In the present embodiment, the case where the excitation light is condensed on the laser crystal 5 using the two optical lenses 2 and 3 has been described. However, the present invention is not limited to such a case. That is, the present invention can also be applied to the case where excitation light is condensed on the laser crystal 5 using one or three or more optical lenses.

  In the present embodiment, an example in which the fiber connector 13 is fastened to the housing body 10 with the mounting screw 16 has been described, but the present invention is not limited to such a configuration. In other words, the laser oscillator according to the present invention can adopt other configurations as long as it can adjust the incident position of the excitation light to the optical lens 2. Further, in the present embodiment, the case where the fiber connector 13 can be adjusted in an arbitrary direction in the plane has been described. However, it is desirable that the fiber connector 13 can be adjusted only in the direction perpendicular to the heat exhaust surface. The structure which can be adjusted only in the direction perpendicular | vertical to a surface may be sufficient.

Embodiment 2. FIG.
In the first embodiment, the example in which the optical axis of the Q switch 6 is adjusted by adjusting the position of the optical fiber cable 8 with respect to the housing body 10 has been described. In contrast, in the present embodiment, a case where the positions of the optical fiber cable 8 and the optical lens 2 with respect to the housing body 10 are adjusted will be described.

  FIG. 11 is an explanatory diagram of the laser oscillator according to the second embodiment of the present invention, and shows a state when adjusting the optical axis of the Q switch. The basic configuration of the laser oscillator is the same as that in the case of FIG. 1 (Embodiment 1), and redundant description is omitted.

  In this laser oscillator, if the positions of the optical fiber cable 8 and the optical lens 2 are moved in arbitrary directions within a plane perpendicular to the central axis of the optical lens 3, the Q switch 6 remains fixed and the laser crystal 5 The path of the excitation light in can be changed. For this reason, the optical axis adjustment of the Q switch 6 can be facilitated in the same manner as in the first embodiment, and is particularly suitable for an air-cooled laser oscillator.

It is explanatory drawing about the laser oscillator by Embodiment 1 of this invention. It is explanatory drawing about a resonator optical axis. It is explanatory drawing about the change of the thermal lens 5R. It is the perspective view which showed an example of the external appearance of a laser oscillator. It is the front view and top view of the laser oscillator of FIG. It is sectional drawing by the AA cut line of Fig.5 (a). 3 is a diagram illustrating a detailed configuration example of a Q switch 6. FIG. It is a figure at the time of seeing the mode at the time of the positioning adjustment of Q switch 6 from the opening part side of the housing body 10. FIG. It is the figure which showed the cross section by the BB cutting line of FIG. It is sectional drawing shown in detail about the principal part of FIG. It is explanatory drawing about the laser oscillator by Embodiment 2 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Resonator housing | casing 2, 3 Optical lens 4 Rear mirror 5 Laser crystal 6 Q switch 7 Output mirror 8 Optical fiber cable 10 Case main body 11 Cover part 12 Sealed space 13 Fiber connector 13F Flange part 14 Lens holder 16 Mounting screw 5R Thermal lens 60 Vibrator 61 Crystal 63 Active aperture 64 Fixing screw

Claims (4)

A rear mirror and an output mirror arranged opposite to each other to form a resonator optical axis;
A laser crystal that is provided on the optical axis of the resonator and stimulates and emits laser light;
An acoustooptic device that controls laser oscillation by diffracting laser light on the resonator optical axis;
A resonator housing for accommodating the laser crystal and the acoustooptic device in a sealed space;
An excitation light supply unit that makes excitation light incident on the laser crystal;
A laser oscillator comprising: an excitation light path adjusting unit for adjusting an incident path of the excitation light to the laser crystal. The excitation light supply unit includes an optical fiber that supplies the excitation light, and an optical lens that transmits the output light from the optical fiber through the rear mirror and collects the light on the laser crystal.
The said excitation optical axis adjustment part consists of an adjustment mechanism for adjusting the relative position of the said optical fiber and an optical lens regarding the direction perpendicular | vertical to the central axis of the said optical lens. Laser oscillator. The excitation light supply unit includes an optical fiber that supplies the excitation light, and an optical lens that transmits the output light from the optical fiber through the rear mirror and collects the light on the laser crystal.
2. The laser oscillator according to claim 1, wherein the excitation optical axis adjustment unit includes an adjustment mechanism for adjusting an attachment position of the excitation light supply unit to the resonator housing. The acoustooptic device is attached to the resonator housing so that the attachment position can be adjusted in a direction parallel to the heat dissipation surface in a state where the heat dissipation surface of the acoustooptic device is in close contact with the inner wall of the sealed space. An acoustooptic device mounting means;
The excitation light axis adjusting unit enables adjustment of the position of the excitation optical axis output from the excitation light supply unit in a direction perpendicular to the heat radiating surface. A laser oscillator according to the above.

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